This tool will launch a new iTerm2 window and create split panes for each session. By broadcasting commands (alt+cmd+i) you have a perfect clusterssh tool.

I used to use https://github.com/wouterdebie/i2cssh for SSH clustering. It's dependant on Ruby and also tends to break on each OSX/Ruby upgrade. I got tired of this, so I made my own version which relies only on python (sys, subprocess, argparse) and the built in OSX osascript binary.

Just download the script to your PATH, then make it executable. Example:

sudo curl -o /usr/local/bin/i2c https://raw.githubusercontent.com/senilio/i2c/master/i2c && \
sudo chmod +x /usr/local/bin/i2c

Be careful when broadcasting your keyboard strokes, as it's easy to unintentionally mess up. See the following screenshot from iTerm2 for a description of the different broadcast modes plus keyboard combinations on how to enable and disable them.

usage: i2c [-h] [-p port] [-l login] [-d] ...

positional arguments:
  servers

optional arguments:
  -h, --help  show this help message and exit
  -p port     Optional: Connect to this SSH port. Defalts to port 22.
  -l login    Optional: Connect as this SSH user. Defaults to current user.
  -d          Enable debug output

Examples:

i2c 10.0.0.{1..5}
i2c root@10.0.0.{1..5}
i2c root@10.0.0.1 user@10.0.0.2
i2c -p 123 -l user 10.0.0.{1..5}
i2c 10.0.0.1 10.0.0.2 10.0.0.3 10.0.0.4

Script will try to enable broadcast mode after creating the new window.